World powers backing opposing Libyan factions had agreed to an arms embargo at a conference hosted by Germany a week ago. The UN has since found that "several" of these countries are not fulfilling their commitment.
Several countries that participated in a Berlin peace summit last week and agreed to respect an existing United Nations arms embargo have violated their commitment, the UN said on Saturday.
The agreement, signed by 16 states and organizations at the Libya peace summit in Germany, set out plans for international efforts to monitor the embargo's implementation.
Read more: Who will monitor a Libya cease-fire?
"Over the last 10 days, numerous cargo and other flights have been observed landing at Libyan airports in the western and eastern parts of the country providing the parties with advance weapons, armored vehicles, advisers and fighters," the UN mission to Libya (UNSMIL) said in a statement.
"The mission condemns these ongoing violations, which risk plunging the country into a renewed and intensified round of fighting," UNSMIL said.
The UN criticized several countries that attended the Berlin summit for violating the embargo, but stopped short of naming them.
Top officials from the United Arab Emirates, Egypt, Russia, Turkey, France, the US, the UK and the European Union were among the peace summit participants.
The UN-backed Government of National Accord, led by Fayez Sarraj in Tripoli, is backed by Turkey, Qatar and Italy — while rival faction Libyan National Army, led by military strongman Khalifa Haftar, is supported by Russia, France, the UAE and Egypt.
Both Sarraj and Haftar refused to meet each other in Berlin as tension remained between the warring factions.
Libya has been in a state of turmoil since the ouster and killing of longtime dictator Muammar Gaddafi in a NATO-backed uprising in 2011.
Fighting in Tripoli has intensified since the LNA launched an offensive to seize the capital in April last year.
shs/stb (Reuters, dpa)